I've had my Samsung Galaxy s3 for over a year now therefore is past its warranty, and basically whenever I turn my wifi/3G on it works for say 30 seconds, until the screen begins to flicker. After flickering for a few seconds my signal drops out and then my screen becomes completely unresponsive. The phone then fully switches off and refuses to turn on for about 30 minutes, then when it does the battery goes down to 2%, no matter how charged the phone was before the crash. I've looked at the actual battery and there's a small bump but I don't really know if that would affect the phone, anyone know what's wrong and what I can do to fix this issue? Thankyou!